Add new certificateProvider extension API.

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index e21192ab20c59297ff9aee26fb99621f3dee71b3..4ab1fc1ddbd46c846f53828bf1df243f76ed31cc 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -57825,6 +57825,8 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="381" label="CAST_DEVICES_PRIVATE_ON_UPDATE_DEVICES_REQUESTED"/>
   <int value="382" label="CAST_DEVICES_PRIVATE_ON_START_CAST"/>
   <int value="383" label="CAST_DEVICES_PRIVATE_ON_STOP_CAST"/>
+  <int value="384" label="CERTIFICATEPROVIDER_ON_CERTIFICATES_REQUESTED"/>
+  <int value="385" label="CERTIFICATEPROVIDER_ON_SIGN_DIGEST_REQUESTED"/>
 </enum>
 
 <enum name="ExtensionFileWriteResult" type="int">
@@ -58947,6 +58949,8 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="1076" label="SYSTEM_DISPLAY_ENABLEUNIFIEDDESKTOP"/>
   <int value="1077" label="BROWSINGDATA_REMOVECACHESTORAGE"/>
   <int value="1078" label="VIRTUALKEYBOARDPRIVATE_SETKEYBOARDSTATE"/>
+  <int value="1079" label="CERTIFICATEPROVIDERINTERNAL_REPORTSIGNATURE"/>
+  <int value="1080" label="CERTIFICATEPROVIDERINTERNAL_REPORTCERTIFICATES"/>
 </enum>
 
 <enum name="ExtensionInstallCause" type="int">